Challenge Questions
Section 2.3
Question 2.39
From 80% to 90% of the most common human chromosome abnormalities arise because the chromosomes fail to divide properly in oogenesis. Can you think of a reason why failure of chromosome division might be more common in female gametogenesis than in male gametogenesis?
Question 2.40
On average, what proportion of the genome in the following pairs of humans would be exactly the same if no crossing over took place? (For the purposes of this question only, we will ignore the special case of the X and Y sex chromosomes and assume that all genes are located on nonsex chromosomes.)
- a. Father and child
- b. Mother and child
- c. Two full siblings (offspring that have the same two biological parents)
- d. Half siblings (offspring that have only one biological parent in common)
- e. Uncle and niece
- f. Grandparent and grandchild
Question 2.41
Female bees are diploid, and male bees are haploid. The haploid males produce sperm and can successfully mate with diploid females. Fertilized eggs develop into females and unfertilized eggs develop into males. How do you think the process of sperm production in male bees differs from sperm production in other animals?
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*This analogy is adapted from K. Nasmyth. Disseminating the genome: joining, resolving, and separating sister chromatids during mitosis and meiosis. Annual Review of Genetics 35:673–745, 2001.